Rotary drive multiple position latch



I March 10, 1964 R. F. HE-RETH ETAL 3,124,012

ROTARY DRIVE MULTIPLE POSITION LATCH Filed March 2, 1962 v INVENTORSPHLPH F HEEZ'TH 650 FIG. 3

United States Patent RQTARY DRIVE MULTlPLE PGSITION LATCH F. llereth,PortOrcliard, and George M. Sherman,

Breme'rton, Wash, assign ors to the United States of America asrepresented by the Secretary of the Navy Filed Mar. 2,1962, Ser. No.177,714 4'Claimfs. (Cl. 74-527) (Granted under Title 35, US. Code(1952), see. 266) The invention described herein may be manutactured andused by or for the Government of the United States of America forgovernmental purposes Without the payment of any royalties thereon'ortherefor.

The present invention relates to latch mechanism and, in particular, tomechanisms for latching rotary members in multiple rotated positions.

Generally considered, a principal object of the invention is to providea multiple position latch for securing a rotary driving or driven shaftin any number of preselected positions.

Another more specific object is to provide such a multiple positionlatch for securing the train and elevation drive shafts Otf a particularlguided'missile launcher system which'will be broadly described.

Still another object is to provide a self-latching rotary drive such asobviates the need for securing the drive by the more conventional meansof extending latch pins or the like into physical inter-engagement withrelatively stationary members.

A further object is to provide a rotary drive multiple position latchthat is functionally related to the drive in a manner capable ofsecuringthe drive at precise increments of rotational advance.

Another object related to the last is to provide such a latch that iscapable of holding a precise position and also capable of automaticallyadjusting its engagement to compensate for an anticipated sag in therotary drive or driven member such as otherwise would result in amisalignment of the latch members and a consequent error in theprecision of the secured position.

A further object is to provide such a latch with a switching mechanismrelated to latch operation in a manner capable of electrically relayinglatch position information.

Another object is to provide a hydraulicallynctuated latch adapted tonormally engage a rotary drive in the absence of hydraulic actuation.

Other objects are to provide a simple, reliable, multiple position latchcapable of precise operation.

In a manner will become clear the objects are achieved by coupling asprocket wheel or the like to the shaft of the drive to be latched and,further by utilizing a driven piston to operate a toggle arrangementwhich carries a pair of latching arms adapted to engage the sprocketwheel. In the preferred form, the toggle also mounts means responsive tolatch actuation for remotely controlling the piston drive. Otherfeatures of the invention will become more apparent in the detaileddescription that is to follow.

The invention is illustrated in the accompanying drawings of which:

FIG. 1 is a perspective illustration of one form of the present latchmechanism;

FIG. 2 is a side elevation of another embodiment of the invention; and

PEG. 3 is an enlarged fragmentary View of a portion of the PEG. 2 latchillustrating in a schematic manner its sag-compensating, selfadjustmentfeature.

Referring to 1, it may be noted that the rotating objector member tobelatched is represented by a drive shaft 1' which may be considered asoperatively coupled to a hydraulic motor (not shown), this motor drivingthrough shaft 1 into suitable gear reduction unit, the out- 3,l24,l2Patented Mar. 10, 1964 2 put of which usually is meshed with a drivergear to impart its motion to a turret or other physical object. In themissile launcher environment, for example, the hydraulic motor isprovided by a B-end motor carriedby a rotating turret which also carriesa pair of launcher arms onto which the missiles are to be loaded.

Considering the presently-involved missile launcher system in greaterdetail, its major components, in addition to its rotatable turret andlauncher arms,- includes a cylindrical magazine having concentric ringsof missilerewiving cells, and a chain hoist mechanism carried by thelauncher arms and adapted to be r-unnably-extended through suitablerails into the magazine cells to engage and hoist the missiles intofiling position on the arms. In a manner that can be visualized, thelauncher arm, as well as the magazine cells, are provided with identicalrail sections which, of course, must be mated or aligned to provide acontinuous track for the chain hoist and for the missile shoes. In thisregard, the missiles carry conventional shoes or lugs which ride in therail sections to provide missile support both in the magazine and on therails, and the hoist accomplishes its lift by engaging the missileshoes. Both the hoist and the shoes then travel in the mack provided bythe mated mail sections.

To form the continuous track it is necessary to rotate the launcher armsinto a position directly over the particular missiles to be fired and,further, since the magazine cells support the missiles in a verticalposition, the arms then must be elevated into a vertical position tocause their rails to vertically align with the magazine rails.

For this purpose, the turret is rotatable about the vertical axis of themagazine and its arms are rotatable on this vertical axis directly overone or the other of the rings of magazine cells. The arms may belaterally shifted in a telescopic manner to accommodate the spacing ofthe concentric rings. Also, the launcher arms are rotatably elevatableabout a horizontal axis so as to permit their elevation into verticalalignment with the magazine rails. It is interesting to note that theserotational movements of the arms also are used to initially aim themissiles to be fired since the movements provide the necessary targettraining and elevation angles.

The latch of the present invention is incorporated in this missilelauncher to secure both the train and elevation movements of the armswhen the arms are rotated or elevated into a missle loading alignmentwith the magazine cells. More specifically, one of the latches is usedto secure the elevation movement of the arms, While the ther secures thearms in a fixed position over any diametrically-opposed pair of magazinecells. The elevation latches, for reasons to be considered, need provideonly two latch positions. However, the train latch, at least in theactual launcher arrangement, must be arranged to secure the arms atevery 2 /2 of rotational advance. The reason for this latter requirementis because the magazine has the previously-mentioned concentric ringarrangement including an outer ring of 24 cells and an inner ring of 18.Consequently, if a launcher arm is to-pick up an outer ring missile, itmust rotate at least 15 from one missile cell to another. Similiarly, ifit is to pick up an inner ring missile, it must rotate at least 20.However, the situation is not quite this simple since the outer andinner rings are radially staggered 2 /2 A one from'the other, the resultbeing that the arms must be capable of being stopped and latched in 2 /2rotational increments of the arms. Also, because of the need forabsolute alignment of the launcher arm rails with the missle rails, theindexing of the arms must be very precise.

The manner in which this latching operation is accomplished provides aprincipal feature of the present invention. Generally, it is achieved bymounting a sprocket wheel 6 on shaft 1 and by utilizing a piston-driventoggle arrangement to open and close the jaws of the latch about thesprocket wheel. Before continuing with structural details, it should benoted that the embodiments of FEGS. 1 and 2 are precisely the sameexcept for the shape of sprocket wheels 6. Thus, in the FIG. 1embodiment, a sprocket wheel having 12 teeth or detents 7 is employed,While in the FIG. 2 embodiment, the sprocket wheel has only two teeth ordetents. Obviously, the two latches are adapted for different purposesand, again relating the mechanism to the missle launcher environment,the 12- detent sprocket wheel is used to latch the train movement of theturret, while the 2-detent sprocket wheel is used to latch the elevationmovement. The latching of the elevation movement requires only twopositions, these being its stowed position and a fully elevatedposition. However, as previously described, the train movement requiresa large number of securable positions, so that the sprocket wheel itselfis provided with an appropriate number of latch positions. However, theactual number of latch positions on the sprocket wheel is a function ofthe gear reduction ratio between the input and output of the rotarydrive. In the particular launcher arrangement, a 60 to 1 gear reductionmay be used between rotary drive shaft 1 and the output and, such beingthe case, it is necessary to have a 12-detent sprocket wheel.

Continuing with reference to FIGS. 1 and 3, features common to bothlatch mechanisms include a supporting hydraulic cylinder mount bracket 8which may be bolted or otherwise secured to approximate stationarystructure such as a surface of the turret or the gear reduction housingwhich itself is carried by the turret. The bracket is formed at itsupper end with a pair of side walls 9 and 11 and a rear wall 12. At itslower end, the bracket is provided with a base portion having laterallyextended flanges 13 and 14 that support the toggle mechanism to bedescribed.

Also supported by bracket 3 is a hydraulic cylinder 16 which mounts apiston 17 having an upper rod portion 13 and a lower rod portion 19,both of which project out wardly through suitable bushings and sealingmembers provided at both ends of the cylinder. An upper cylinder head 21is used to mount a sleeve member 2-2 that carries a spring 23 betweenits upper end wall and a spring retainer flange 24 formed on rod portion13, which, as shown, projects into the sleeve member. Spring 23 exertsits resilient pressure on the upper end of the piston to normally urgethe piston in a downwardly direction (FIG. 2).

To drive the piston, hydraulic fluid lines 27 and 23 lead into the upperand lower ends of cylinder in and it will be apparent that, when fluidis supplied through line 28, the piston is moved upwardly against theforce of spring 23.

The toggle mechanism which carries the latching members is secured tolower piston rod extension l) by a clevis 29, this clevis having a pin31 in which a pair of laterallyextending toggle links 32 and 33 are hungin a conventional manner. Also, the outer ends of each toggle links 32and 33 are pivotally coupled to a pair of rocket arms 34 and 36, thesearms each being provided at their upper ends with a similar clevis 37carrying pins 33 by means of which the couplings are made. The lowerends of rocker arms 34 and 36 carry the latching members of the togglearrangements, these latching members being in the form of rollers 39 andil supported on pins 42 and 43 carried by the rocker arms. As would beexpected, the rollers are sized to fit into teeth or detents 7 of thesprocket wheels and the arrangement is such that the latch rollers arecarried by the toggle on diametrically opposite sides of the sprocketwheel to engage the wheel at a 186 circumferential spacing and hold thewheels in fixed and latched positions.

To provide the desired pivotal motion to move the rocker arms into andout of latch engaging position, each of the rocker arms is pivotallysecured by pins 44 and 46 to flanges 13 and 14 of the cylinder mountbracket in the manner illustrated. Consequently, vertically reciprocalmovement of the piston causes each of the rocket arms to pivotallyrotate about the axis of their inter-connection with pins 4-4 and as ofthe cylinder mount bracket. More specifically, an upward movement of rod19 from its illustrated position causes links 32 and 33 to swing theirpins 38 inwardly about pins 44 and 46. Latch rollers 39 and 41, in turn,swing outwardly to release their latching engagement with the sprocketwheel detents. Obviously, a downward return stroke moves the rollersback into latching engagement.

Another feature of the invention is the provision of a switch mechanismadapted to provide an indication of a latched or unlatched condition,or, if desired, to provide remote control for the shutting off orinitiating the power producing the rotary drive of drive shaft 1.

The particular switch mechanism employed is closely coordinated with themovements of rocker arms 34 and 36 by being mounted on a bracket 47which, in turn, is bolted to flange 14 of cylinder mount bracket 8. Theswitches themselves are conventional plunger type switches 43 and 49provided with plunger arms 51 and 52 which project inwardly towardcontact plates 53 and 54- carried by rocker arm 36. Consequently, therocking movement of the arm depresses the upper or lower plungerdepending upon whether the latch is opened or closed. In other words,when the latch is closed, as shown in FIG. 2, upper plunger 52 engagesthe upper contact plate 54 and is depressed in a manner which will beapparent. When the latch is released, the rocking movement depressesplunger 51.

The operation of the mechanism should be relatively clear from theforegoing description. Considering the example of the missile launcherapparatus which had been briefly outlined, if it is desired to latch thetrain movement of the rotary turret, a latch having a sprocket wheelsimilar to the FIG. 1 sprocket wheel may be employed. As already notedthis latch has 12 teeth or detents which, because of the particular gearreduction ratio employed,

ermits the train movement to be latched at each of the missile cellpositions defined by the inner and outer cell arrangement of themagazine.

In the assumed situation, the Bend motor producing the turret rotationaldrive is permitted to impart its drive to the input shaft and,simultaneously, hydraulic pressure is supplied to hydraulic cylinder 16of the latch mechanism through pressure line 28 to move the pistonupwardly and cause the rocker arms to rock outwardly into a latchrelease position. In the actual mechanism, the rotational advance of theturret is closely controlled by a precise indexing mechanism whichpermits a reasonably rapid advance until the final approach of theturret to its selected disposition over the missile to be loaded. Also,suitable valves and relays are provided so that, at precisely the momentthe turret brings its launcher arms to the desired position, pressure isreversed in tank and pressure lines 27 and 28 to cause the piston tomove downwardly to engage latch rollers with the teeth of the sprocketwheel. At the same time, the rocking movement strikes upper plunger 52of the switch mechanism. As also may be noted, sprocket wheels 6 of bothembodiments are couplcd to input shaft 1 by a flexible coupling which isa conventional disk-type coupling. A further feature which has not beenmentioned but which is apparent in the arrangement is the fact that anyloss of hydraulic pressure results in piston 17 being driven downwardlyby spring 23 so as to latch the rotary drive and the turret in the fixedposition.

FIG. 3 illustrates still a further important functional advantage ofthis type of multiple position latch. Thus, in some applications,including the missile launcher one, it can be expected that there willbe some sag in the power drive which, because of the precision required,should be compensated in some manner. The present sprocket-type latchprovides this compensation by centering itself in the bottom of eachsprocket-wheel detent as the latch rollers close into latchingengagement. If, for example, a sag is present such as would causerollers 39 and 41 to strike in the dotted line position shown in FIG. 3,the rollers produce a sprocket movement necessary to reposition thedetents precisely so that the rollers actually engage in their full lineposition. Such a repositioning compensates for the sag which in themissile use may be as high as 8.

In general, the latch mechanism described provides an unusually simpleand thoroughly reliable and sturdy mechanism for precisely latching arotary drive at predetermined increments of rotational advance, theseincrements being, in a sense built into the mechanism by providing thesprocket wheel with a proper number and spacing of teeth or detents.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. Apparatus for latching a rotary member in a plurality of rotatedpositions comprising a wheel, means coupling the Wheel for rotation withsaid rotary member and provided peripherally with a plurality ofdetents, a support bracket formed with a pair of flange membersprojecting outwardly in opposite directions, a reciprocably fluidpressure driven member carried by said support bracket, a pair of togglelinks pivotally coupled on a common axis to said driven member andextending outwardly from said common axis generally parallel to saidflanges, a rocker arm pivotally coupled at one end to the outer end ofeach of said toggle links, latch means carried by the other end ofrocker arms, and means pivotally coupling the outer end of each of saidflanges medially to each of said rocker arms, said links, arms andflanges forming a toggle arrangement supporting said latch means indiametrically-opposed positions on either side of said wheel, saidtoggle swingably moving said latch means into and out of detent-engagingpositions.

2. The apparatus of claim 1 further including a pair of switches carriedby one of said flange members in position for being operatively engagedupon said pivotal opening and closing movements of their proximate latcharm.

3. The apparatus of claim 1 wherein said detents are formed as teeth forreceiving said latch means, and said latch means include a rolleradapted for engaging the inner surface of said indentations, saidadjacent teeth being spaced one from the other a predetermined distancepermitting initial engagement of said rollers on said teeth portions andsubsequent repositioning of the wheel by the rollers to compensate foraxial misalignment of said gear input and output.

4. The apparatus of claim 1 wherein said driven means includes acylinder, a piston mounted in the cylinder, mechanical means resilientlyurging said piston into latchengaging position, and fluid pressure meansfor reciprocally moving said piston into latch-dis-engaging position.

References Cited in the file of this patent UNITED STATES PATENTS2,315,597 Conrad Apr. 6, 1943 FOREIGN PATENTS 176,536 Switzerland July1, 1935 575,793 Great Britain Mar. 5, 1946

1. APPARATUS FOR LATCHING A ROTARY MEMBER IN A PLURALITY OF ROTATEDPOSITIONS COMPRISING A WHEEL, MEANS COUPLING THE WHEEL FOR ROTATION WITHSAID ROTARY MEMBER AND PROVIDED PERIPHERALLY WITH A PLURALITY OFDETENTS, A SUPPORT BRACKET FORMED WITH A PAIR OF FLANGE MEMBERSPROJECTING OUTWARDLY IN OPPOSITE DIRECTIONS, A RECIPROCABLY FLUIDPRESSURE DRIVEN MEMBER CARRIED BY SAID SUPPORT BRACKET, A PAIR OF TOGGLELINKS PIVOTALLY COUPLED ON A COMMON AXIS TO SAID DRIVEN MEMBER ANDEXTENDING OUTWARDLY FROM SAID COMMON AXIS GENERALLY PARALLEL TO SAIDFLANGES, A ROCKER ARM PIVOTALLY COUPLED AT ONE END TO THE OUTER END OFEACH OF SAID TOGGLE LINKS, LATCH MEANS CARRIED BY THE OTHER END OFROCKER ARMS, AND MEANS PIVOTALLY COUPLING THE OUTER END OF EACH OF SAIDFLANGES MEDIALLY TO EACH OF SAID ROCKER ARMS, SAID LINKS, ARMS ANDFLANGES FORMING A TOGGLE ARRANGEMENT SUPPORTING SAID LATCH MEANS INDIAMETRICALLY-OPPOSED POSITIONS ON EITHER SIDE OF SAID WHEEL, SAIDTOGGLE SWINGABLY MOVING SAID LATCH MEANS INTO AND OUT OF DETENT-ENGAGINGPOSITIONS.